Shoe filler composition and method of making



Patented Dec. 24, 1935 SHOE FILLER COMPOSIITIONYAND METHOD OF MAKING Harry H. Beckwith, Brookline, assignor to Beckwith j Manufacturing Company,

Boston,

- Mass, a corporation of Massachusetts No Drawing. Original application February 6,

' 1928,'Serial No. 252,431. Divided and this ap- 'plicationSep'te'mber' 14, 1929,Serlal No. 392,748. Renewed December 20, 1932 8 Claims.

.This invention relates to compositions partic-' ularly suitable for use as fillers between the inner and outersoles' of shoes, more particularly welt shoes, and within the innersole stitch receiving rib. It further relates to a method of making such compositions. Such compositions should be capable of being easily placed in position, be in a plastic condition, and should'set within a reasonable time and without material shrinkage into a tough, flexible mass. This mass should be yieldable to the fiexing of a shoe during walking and should not be displaced under the pressure of the foot at any temperature conditions to which it is likely'to be subjected, and it should not contain material injurious either to the shoe materials or to the foot; Material heretofore used for this purpose has not been entirely satisfactory as to many 'of these requirements and has commonly had'the further disadvantage of requiring heat treatment with its attendant great danger of damage by overheating to condition'it for application to the shoe.

The composition of the present invention does not require heati'ngbut may be placed in-the shoe in plastic condition at room'temperature. It sets in about an hour into a flexible, stretchable mass, completely filling the space desiredtand which can not thereafter be' displaced or rendered plastic under any conditions which are likely to be encountered in service.

In general, this composition when in 'condi tion to be applied to the shoe comprises an aqueous dispersion of rubber of natural or artificial variety, mixed with one or more fillers which are preferably non-water-absorbent. Various inert fillers, such as talc, granulated cork, cellulose fiber, asbestos fiber, which are waterabsorbent, may be rendered non-water-absorbent by treatment with a suitable waterproofing material, and then employed in the composition of the present invention, although one may start with a filler which is initially non-water-absorbent, such as ground vulcanized rubber scrap. When talc, granulated cork, or the like, is employed, it is preferably treated with melted wax tailings, bitumen, or other suitable waterproofing material, before being mixed with the aqueous rubber dispersion, so that absorption of the water of the dispersion by the filler is avoided and no difliculty in drying out and setting the rubber is encountered. The composition of the present invention is plastic when moist, but on drying the rubber coagulates and the material can not thereafter be reduced to plastic condition merely by addition'of water or by temperature treatment, or both. In drying, the composition shrinks very little and clings firmly to the shoe parts, so that when dry it completely fills the inseam and can not become displaced as by the 5 pressure of the leveling operation or made lumpy due to the non-uniform pressure exerted thereon during the use of the shoe. It may, moreover, be made of neutral stock so that it has no deleterious elfect either on the shoe materials or 10 on the wearers foot. Italso becomes waterproof on drying. If the outersole is applied before it is dry, itacts to cement or-bond the outersole to the innersole, and serves as a waterproof, heatinsulating layer which will not move, crawl, or 15 crack in service, and which will stand wear even. when the outersole is wornthrough. With the parts so bonded, the shoe will not squeak. It can also'be used on the heel portion to form a smooth inside heel seat.

By using the composition of thepresentinvention, the desired rubber compound may be 00-, agulated in place in the shoe, as by drying, and it, is possible todo away with the expense, and explosion' and fire hazard, incident to the use. of 25 shoe filler compositions comprising rubber solutions, so-called, containing volatile, combustible, organic solvents, such as benzol or gasoline. Again, it is easy to effect auniiorm mixture of an aqueous rubber dispersion with the desired claimed stock is warmed up on a standard rubber mill for, say, 35 minutes. It is then transferred to a cool, jacketed mixer of the Werner and Phleiderer type with the special blades known as the Pratt blades, and allowed to pull for 10 minutes, about pounds of the rubber being a normal charge. Then three two-quart shots of water are, added at intervals of 8 minutes, While the pulling is continued. Twelve and three-fourths pounds of grade M rosin are then added and the mixer is then subjected to steam at about 30 pounds pressure for 30 minutes while the pulling and mixing is continued. 55

The steam is then turned off and cooling Water is circulated through the jacket of the mixer and after 10 minutes of pulling another two-quart.shot of water is added and after 5 5 minutes more two quarts more of water are added. Five minutes later 14 pounds and ounces of Wilkenite clay made into a 1 to 1 paste with water are added. After 45 minutes of additional pulling four two-quart shots of water are added 10 at 8 minute intervals, together with 7 grams of v preservatives such as thymol, benzoate of soda, or the like. As soon as the water has disappeared from the surface the charge is dumped, the dispersion being complete. Fifteen parts by weight of talc which has preferably been rentalc, besides acting as a filler, causes the composition to spread smoothly and easily, and the rosin increases its adhesive properties. In place of oil-reclaimed rubber, rubber reclaimed by either the acid or alkali process employed when 25. fabric is to be removed from the old rubber might be used but this should be neutralized so as not to attack the shoe parts or the foot. Due to the difiiculty of insuring exact neutralization, however, oil-reclaimed stock is preferred since emithis is in neutral condition. Likewise, natural latex of the proper concentration may be used in place of the artificial dispersion, though the artificial dispersion of reclaimedrubber is quite satisfactory, since characteristics such as high 35 tensile strength are of no particular moment in a set shoe filler composition. Artificial dispersions of reclaimed. rubber, usually being less expensive than latex, may indeed be preferable to latex, which is at present ,procurable on the 40 market only from comparatively few sources.

This filler composition is applied while moist when it is in a plastic condition. As soon as the water content evaporates, it sets and the rubber H coagulates, no heat treatment of the material being necessary at any stage of its application to the shoe. Should it be desired to do so, of course, a vulcanizing agent and accelerator could be added so that the filler might be vulcanized. So far as certain subject matter is concerned,

50' this application is a division of my application Serial No. 252,431, filed February 6, 1928.

' Having thus described the nature of this composition and a procedure by which it may be produced, it should be evident to those skilled in the art that various modifications might be made or practised without departing from the spirit or scope of this invention as defined by the appended claims. 5

Iclaim: f 1

1. A shoe filler composition which is spreadable and plastic at room temperature, comprising an aqueous dispersion of rubber containing rosin mixed with granulated cork, the particles of 10 which are coated with waterproofing material.

2. A shoe filler composition which is spreadable and plastic at room temperature, comprising approximately 85 parts of an aqueous dispersion of rubber of about 70% solids content 15 mixed with about 15 parts of granulated cork, the particles of which are coated with waterproofing material.

3. A shoe filler composition which is spreadable and plastic at room temperature, comprising an 20 aqueous dispersion of reclaimed rubber mixed with granulated cork, the particles of which are coated with waterproofingmaterial.

4. A process'which comprises dispersing rubber along with rosin in water and adding tothe aqueous dispersion granulated cork, said cork granules having been precoated with waterproofing material.

5. Ashoe filler composition which is spreadable and plastic at room temperature, comprising an aqueous dispersion of rubber mixed with waterproof, granulated cork, the particles of which are coated with waterproofing material.

6. A composition which is especially adapted for filling shoe bottoms and which is spreadable and plastic at room temperature, comprising anaqueous dispersion of rubber mixed with waterproof, granulated cork, the particles or which are coated with thermoplastic waterproofing material. 1 40 '7. A composition which is especially adapted for filling shoe bottoms and which is spreadable and plastic at room temperature, comprising an aqueous dispersion of rubber mixed with waterproof, granulated cork, the particles of which are aqueous dispersion of rubber mixed with water- 5 proof, granulated cork, the particles of which are coated with bitumen.

'' HARRY H. BECKWITH. 

